NorCon Power Partners, L.P. - Executive Summary |
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Accident Release Prevention and Emergency Response Policies NorCon's Risk Management Planning policy provides a comprehensive approach to prevent accidental releases of chemicals through the integration of engineering controls, administrative controls, and administrative procedures. All applicable procedures from the U.S. Environmental Protection Agency (EPA) Prevention Program are adhered to. The NorCon emergency response program involves the preparation of response plans detailed specifically to the NorCon located in North East, Pennsylvania and to the emergency response services available in the community as detailed in the NorCon Off-Site plan submitted and approved by the Erie County Local Emergency Planning Commission (LEPC), and is in compliance with the EPA Emergency Response Program requirements. Stationary Source and Regulated Substance Handled The NorCon facility, located at Ackerman Lane, North East, Pennsylvania is an 80 MW Cogeneration Facility. The facility produc es electricity and process steam which are both sold under contract to Niagara Mohawk Power Corporation and Welch, Foods, Inc. Anhydrous ammonia is used as a refrigerant. The anhydrous ammonia system contains bulk tanks, process piping, various safety and monitoring systems, and various chillers. Operators are on staff to respond to any alarms and maintain the system. The offsite consequence analysis includes consideration of two releases for this chemical, the "worst case release scenario" and an "alternate case release scenario." The worst case scenario is defined by the RMP regulation and states that "the owner or operator shall assume that themaximum quantity in the largest vesselis released as a gas over 10 minutes," due to an unspecified failure. The alternate case scenario is defined as "more likely to occur than the worst case release scenario." Worst and Alternate Case Release Scenarios Atmospheric dispersion modeling has been performed to determine the potential dis tance traveled by the anhydrous ammonia before its concentration decreases to the "toxic endpoint" specified in 40 CFR Part 68 Appendix A, which is 0.14 mg/L of air (200 ppm). The residential population within a circle with a radius corresponding to the toxic endpoint distance has to be defined, "to estimate the population potentially affected". The worst case scenario involves a failure of the bulk ammonia tank, containing 13,085 lbs. of ammonia, released as a gas over a 10-minute period. EPA mandated meteorological conditions, namely Stability F, wind speed of 1.5 meters per second, highest daily temperature of 98oF (as supplied from 1995-1997 PADEP Erie COPAM Station data), and average humidity of 68% (three year average of 1996-1998 as supplied by the PADEP Erie COPAM Station) were used for the worst case scenario. The facility is located in a rural area; the worst case scenario would encompass population and environmental receptors. The alternate case scenario involves the o verpressurization and venting through relief valve PSV055A/B due to a plugged strainer (S210). The release duration time is conservatively set at 20 minutes to account for the amount of time it might take the operator to become aware of the release and close the manual valves. Meteorological conditions used for the alternate case scenario were ambient wind speed of 3 m/s, temperature of 98oF, atmospheric stability class D and relative humidity of 68%. The alternate case would also affect offsite population but no environmental receptors. General Accidental Release Prevention Program and Prevention Steps The general accidental release program for anhydrous ammonia is as follows: 7 Safety training for employees who maintain and inspect the system. 7 Effective, detailed procedures for maintenance, operation and troubleshooting of the systems. 7 Preventative maintenance programs to maintain a good mechanical integrity of the system. 7 The Management of Change program identifies poten tial concerns before system changes are implemented. 7 Detailed inspection program to identify potential concerns before they become a problem. The inspection program includes low level leak detection activities. 7 A compliance audit program that meets the criteria of OSHA's PSM standard (29 CFR 1910.119). 7 Chemical specific prevention steps for anhydrous ammonia include Level B and Level C personal protection equipment to be used for emergency response and certain other activities; training of emergency responders and maintenance employees on the toxic and physical properties of ammonia; the chemical sensing system and other safety systems. A Process Hazard Analysis (PHA) meeting the criteria of OSHA's PSM standard 29 CFR 1910.119 was conducted for the anhydrous ammonia system. A combination of the What-if and FMEA methods was used to analyze the anhydrous ammonia system. A team consisting of safety and environmental professionals and plant engineers analyzed the ammonia system. In regards to the mechanical integrity portion of PSM, the standard ANSI K-61.1 was used to evaluate the safety and integrity of the system. Five Year Accident History There has been one accidental release of anhydrous ammonia within the past five years. In January of 1998, a release occurred from the relief valves on the condenser and defrost gas generator vessels due to high pressure in the system. It was determined that a change in load on the ARP resulted in an increase of steam supplied to the desorber. The increase in steam caused pressure to increae in the system. The increase in pressure was not sensed due to a plugged sensing line. This resulted in insufficient cooling water to the condensers and the pressure in the condensers and defrost gas generator increased to the relief valve set point of 261 psi. The ammonia gas was then vented to the atmosphere. A manual emergency shutdown was initiated on the ARP. No employees or public were injured as a result of the rele ase. An offsite responder was notified and responded. As a result of the accident, a local pressure reading from the condenser is being documented as part of the daily log readings and compared to the desorber remote pressure transmitter to make sure a differential pressure does not exist. Also, the two high pressure shutdown switches have been split from a common pressure source. This will prevent a single source failure. Emergency Response Program NorCon has a comprehensive emergency response plan, including an Off-Site plan that has been approved by the Erie County Local Emergency Planning Commission (LEPC). NorCon has emergency responders trained at the 24-hour technician level (OSHA HAZWOPER standard), as well as the Incident Commander level. These responders are trained to handle potential releases of anhydrous ammonia. Specific on-site response plans for handling releases of anhydrous ammonia exist. The emergency response team is well equipped with chemical sensing equ ipment; personal protective equipment; offensive and defensive strategy tools & equipment; radio communication; pre-determined response checklists for Incident Command, first aid responders, EMT's and medical supplies. All NorCon emergency response teams (fire, chemical and other emergency situations) use the Incident Command System. This system includes provisions for interaction and support of off-site professional emergency responders. Planned Changes to Improve Safety To improve safety at NorCon, a search for more reliable ammonia sensors that require less maintenance is being conducted. Also, sensors for the venting system are being considered to better detect ammonia leaks that may occur. There is also a review/discussion of the OSHA PSM program at the safety meetings which are conducted on a monthly basis to assist in improving safety. |